add the clients, if the name is not the real name, change it in the clients munin-node.conf (all lowercase !)

force the update

su - munin --shell=/bin/bash -c /usr/share/munin/munin-update

check the data at the server: http://<ip>/munin/index.html

Client

SOMETHING IS WRONG HERE, DON'T THINK THE FOLLOWING IS CORRECT!
It has something to do with the client checks. Hard discs etc. are checked on the server.
When I use Munin again, I will correct this. Perhaps.